Alternate action mechanism for pushbutton switch with flat-headed latching pin

ABSTRACT

A push button switch comprising a housing containing a plurality of contacts, a push button slider having a cam track in one surface thereto and being adapted to be inserted into the housing to connect selected contacts in pairs, the slider being biassed towards a position of rest; and a flat headed straight pin inserted through a slot in the housing perpendicular to the longitudinal axis of the slider into engagement with the cam track of the slider. An enlarged flat head on the pin is held between a flat surface surrounding the slot and a retaining plate, so that the pin remains perpendicular to the plane of the upper surface of the slider. On successive depressions of the slider, the pin moves across the transverse slot in the housing and along the path of the cam track to control the degree of ingress of the slider in the housing.

United States Patent Davies [is] I 3,707,610

[72] Inventor: Gwyn Davies, Cwmbach, England [73] Assignee: A. B. Electronic Components Limited, Abercynon, Glamorgan,

England 22 Filed: April5,197l 21 Appl. No.5 131,051

[30] Foreign Application Priority Data April 7, 1970 Great Britain ..l6,519/70 52 US. Cl. .L ..200/153 J [51] Int. Cl. ..1101l1 13/56 [58] Field of Search ..200/ 153 J [5 6] References Cited UNITED STATES PATENTS 3,624,328 11/1971 Hausen ..200/153 J 3,229,548 1/1966 Du Temple De Rougemont et al. ..200/l53 J 3,582,592 6/1971 Schadow ..200/l53 J Dec. 26, 1972 FOREIGN PATENTS OR APPLICATIONS 1,164,260 9/1969 Great Britain ..200/153 J Primary Examiner-Robert K. Schaefer Assistant Examiner-Robert A. Vanderhye Attorney-Steward 8L Steward [57] ABSTRACT A push button switch comprising a housing containing a plurality of contacts, a push button slider having a cam track inone surface thereto and being adapted to be inserted into the housing to connect selected contacts in pairs, the slider being biassed towards a position of rest; and a flat headed straight pin inserted through a slot in the housing perpendicular to the longitudinal axis of the slider into engagement with the cam track of the slider. An enlarged flat head on the pin is held between a flat surface surrounding the slot and a retaining plate, so that the pin remains perpendicular to the plane of the upper surface of the slider. On successive depressions of the slider, the pin moves across the transverse slot in the housing and along the path of the cam track to control the degree of ingress of the slider in the housing.

4 Claims, 2 Drawing Figures PATENTEDHEBZB 1912 3.7016 1 0 BWVN DAVIES.

ATTORNEY ALTERNATE ACTION MECHANISM FOR PUSHBUTTON SWITCH WITH FLAT-HEADED LATCHING PIN The present invention relates to push button switches. I

According to the present invention a push button switch comprises a housing containing a plurality of contacts, a push button slider having a cam track in one surface thereof and being adapted to be inserted into the housing to connect selected contacts in pairs, the slider being biassed towards a position of rest. A camfollower, comprising a pin with a large flat head at one end, is inserted through a slot in the housing perpendicular to the longitudinal axis of the slider into engagement with the cam track of the slider, the head of pin being retained between the housing and a retaining plate, so that the shank of the pin is perpendicular to the plane of the upper surface of the slider. Thus, on successive depressions of the slider, the pin moves across the transverse slot in the housing and along the path of the cam track to control the degree of ingress of the slider in the housing.

According to a preferred aspect of the present invention the cam track is substantially heart-shaped.

The invention will now be more fully described by way of example, with reference to the accompanying drawings, wherein:

FIG. 1 is an exploded view of a push button switch according to one embodiment of the present invention.

FIG. 2 is a diagrammatic plan view of the heartshaped cam track shown in FIG. 1, illustrating the pin shown in FIG. 1, in various positions along the cam track.

A push button switch comprises a push button slider l, a housing 2, and a straight pin 3. The housing 2 contains a plurality of contacts 4, and has an opening 5 in one end through which the push button slider 1 can be inserted, and a transverse slot 6 through which one end of pin 3 is inserted into the housing. The push button slider 1 has a heart-shaped cam track or groove 7 in its upper surface and a pair of recesses 8 into each of which a spring contact 9 is fitted so as to bridge a pair of contacts 4 on the appropriate side of the housing 2.

The shank of pin 3 is inserted through the slot 6, which runs perpendicular to the longitudinal axis of the slider 1, into engagement with the heart-shaped cam track 7, and the underside of a large flat head 3a at the outer end of pin 3 rests on the flat surface of housing 2 surrounding slot 6 where it is held by a retaining plate 10, so that the shank of pin 3 is retained in a position perpendicular to the plane of the upper surface of the push button slider 1. The plate 10 is formed integrally with an anchoring portion 10a fitting over the slider 1 in register with the opening 5 and having flanges 10b, which it position on the end of housing 2. In order to prevent any tilting of pin 3 whatsoever, plate 10 may be resilient and bear against the upper side of its head 3a, thereby urging the head 3a against the flat upper surface of housing 2. The push button slider l is biassed towards a position of rest by means of a spring 11 positioned between the anchoring portion 10a of the retaining plate 10 and a stop 12 mounted in slots 12a on the push button slider 1.

In operation the slider 1 is depressed and moves into the housing 2. The pin 3 moves from position A across the transverse slot 6, guided by the nose 15 and the cam track 7 which is advancing into the housing 2, to a first stop position B, where further ingress of the slider 1 is prevented by the pin 3. Release of pressure on the slider 1 causes it to move towards its position of rest, under the influence of the spring 11, and the pin engages a nose 13 thus causing the pin to move across the transverse slot 6, and along the cam track to a second stop position C, thus preventing further egress of the slider from the housing. Further depression of the slider 1 causes the pin 3 to engage behind a nose l4 and to move across the slot 6, and along the cam track 7 to point D, where further ingress of the slider 1 is prevented by pins 3. Release of pressure on the slider 1 causes it to move towards its rest position under the influence of the spring 11, the pin 3 moving across the transverse slot 6 and along the cam track 7 to its initial position A to complete a cycle of operation.

When the slider 1 is held by the pin in the position A, the spring contacts 9 bridge between the center or outer contacts 4 on each side, and when the slider is held by the pin in the position C, the bridging is between the center and inner contacts 4.

I claim: I

1. In a push button switch comprising a housing with a plurality of fixed contacts, a push button slider movable within said housing, a cam track formed in a surface on the slider within the housing and extending in the direction in which the slider moves, contact means mounted on the slider and movable therewith to bridge selected pairs of the fixed contacts, means for biasing the slider outwards from the housing, the housing having a flat outer surface disposed parallel with said camtrack surface on the slider and having a slot in said surface extending transversely of the direction of reciprocating movement of the slider, a cam-follower extending through the said slot into operative engagement with said cam track in order to limit, on successive depressions of the slider against its biasing means, the extent of ingress of the slider into the housing and of subsequent egress thereof under the influence of the biasing means;

the improvement wherein said cam-follower comprises a pin having a straight shank and an enlarged flat head at one end,

the shank of said pin being slidable in said transverse slot with the adjacent side of said enlarged head resting substantially flush with the flat outer surface on the housing and having in combination therewith a retaining plate mounted on the housing for engagement with the opposite side of said enlarged head in order to maintain said head flush with said flat outer surface between said housing and retaining plate, such that the shank of said pin is held substantially perpendicular to said cam-track surface as said cam track slides said pin within said transverse slot.

2. A push button switch as claimed in claim 5, in which the cam track is substantially heart shaped.

3. The improvement in a push button switch as defined in claim 1, in which said retaining plate is resilient and has an anchoring portion surrounding said slide with means by which to fasten it to said housing. 

1. In a push button switch comprising a housing with a plurality of fixed contacts, a push button slider movable within said housing, a cam track formed in a surface on the slider within the housing and extending in the direction in which the slider moves, contact means mounted on the slider and movable therewith to bridge selected pairs of the fixed contacts, means for biasing the slider outwards from the housing, the housing having a flat outer surface disposed parallel with said cam-track surface on the slider and having a slot in said surface extending transversely of the direction of reciprocating movement of the slider, a cam-follower extending through the said slot into operative engagement with said cam track in order to limit, on successive depressions of the slider against its biasing means, the extent of ingress of the slider into the housing and of subsequent egress thereof under the influence of the biasing means; the improvement wherein said cam-follower comprises a pin having a straight shank and an enlarged flat head at one end, the shank of said pin being slidable in said transverse slot with the adjacent side of said enlarged head resting substantially flush with the flat outer surface on the housing and having in combination therewith a retaining plate mounted on the housing for engagement with the opposite side of said enlarged head in order to maintain said head flush with said flat outer surface between said housing and retaining plate, such that the shank of said pin is held substantially perpendicular to said cam-track surface as said cam track slides said pin within said transverse slot.
 2. A push button switch as claimed in claim 5, in which the cam track is substantially heart shaped.
 3. The improvement in a push button switch as defined in claim 1, in which said retaining plate is resilient and has an anchoring portion surrounding said slide with means by which to fasten it to said housing.
 4. The improvement in a push button switch as defined in claim 3, wherein said resilient retainiNg plate urges said enlarged head on said pin into engagement with said flat outer surface on the housing. 